Molluscs, especially slugs and snails are known to cause severe plant damages by feeding on them during the entire season of plant vegetation and especially in months with a large quantity of rainfalls and relatively low temperatures. Various molluscicides have been proposed in the state of art for combating snails and slugs featuring various efficacy and properties.
In general molluscicides may be divided into three groups. These are contact-action molluscicides, such as aluminium and copper sulphate crystals, which are applied to the area inhabited by molluscs and adhere to snails or slugs moving in this area; irritant powder molluscicides, such as silica grains, which act by being taken up in the snail's or slug's locomotion mucus; and stomach-action molluscicide baits which are ingested by molluscs.
Most of the molluscicide baits are delivered in a form of granulated pellets to be scattered over the entire field or only in the specified centres of molluscs' occurrence. Application should usually be repeated during the season since in a given moment the pests usually exist simultaneously in different phases of their growth and development.
Molluscicide bait is usually a composition containing at least one molluscicidal agent and a feed bait base.
Common molluscicidal agents include metal chelates, metaldehyde and methiocarb. One of the safest and ecological stomach-action method for combating molluscs involves molluscicidal agents in the form of salts or chelates of iron (III) (cf. Henderson, et al. Crop Protection, 9, 131-134, (1990), WO 89/01287, U.S. Pat. Nos. 5,437,870, 6,447,794, 6,703,036, EP 1752043, WO 03/069996, WO 03/079781, US 2007/0148203, WO 97/26789, WO 2004/075634, AU 689399, AU 697781, AU 735902, PL 195194). Exemplary preparations of this kind which are commercially available include Ferramol® and Sluggo® (containing iron (III) phosphate and EDTA and/or EDDS) or Multiguard® (containing 6% of Fe(III)EDTA chelate).
International publications WO 2009/048345, as well as Polish patent application P. 396674 also disclose molluscicide bait comprising iron powders and/or iron alloys powders as molluscicidal agent, at least one complexing agent; and molluscs' edible agent. Preferred complexing agents are ethylenediaminetetraacetic acid (EDTA) or methylglycinediacetic acid (MGDA) and/or mixtures thereof with other, particularly biodegradable, complexing agents. Such a mixture of iron powder and EDTA forms iron(II) EDTA chelate in situ only after it reaches the molluscs gut.
Common feed bait bases include starch matrix like cereal meals, preferably with bran, sugar, yeast (cf. publications U.S. Pat. Nos. 3,090,723, 4,251,946), fish meal or phagostimulants (cf. EP 1752043).
Furthermore molluscicide baits may contain other constituents including but not limited to substances against mould growth such as IPBC, DCOIT or sorbic acid; alerting (aversive) agents such as Bitrex®; rain-resistance improving agents; granulate extrusion process improving agents such as kaolinite or modified starch; additional attractants such as red clover, paraldehyde, isoamyl acetate, 2-methyldecanol (cf. JP 2004026662) or sulfur compounds (cf. WO 2002/063960); and other known additives.
The object of the present invention has been to provide molluscicide having a form of food bait which would be more efficient and economically reasonable than known molluscicide compositions, harmless to other animals and free of unwanted side-effects.
The inventor unexpectedly discovered that addition of a humic acid to a molluscicide composition displays excellent efficiency in attracting and combating molluscs.